1. Field of the Invention
The present invention relates to a light emitting device.
2. Related Background Art
In recent years, light emitting devices that emit light having a plurality of wavelengths (colors) have been developed. Patent Literature 1 (Japanese Unexamined Patent Application Publication No. 2008-159606) discloses a nitride semiconductor light emitting device comprising a GaN semiconductor layer formed on a GaN substrate, the GaN semiconductor layer including a first and second quantum well layers that emit light having different wavelengths. A color mixture of colors of light components emitted from the first and second active layers is observed. Patent Literature 2 (Japanese Unexamined Patent Application Publication No. 2008-218645) discloses a light emitting device comprising a blue light emitting diode chip and a yellow light emitting diode chip that are mounted on a supporting substrate, thereby producing white light obtained by mixing light components emitted from the two light emitting diodes. Patent Literature 3 (Japanese Unexamined Patent Application Publication No. 2008-235804) discloses a light emitting device comprising a group-III nitride semiconductor substrate and an active layer, the group-III nitride semiconductor substrate emitting longer-wavelength light induced by absorption of ultraviolet light, and the active layer being disposed on the group-III nitride semiconductor substrate and emitting light including the ultraviolet light component. Patent Literature 4 (Japanese Unexamined Patent Application Publication No. 2004-253592) discloses a white light emitting device comprising an InGaN-LED that emits blue light and a ZnSSe fluorescent plate that emits yellow light induced by absorption of the blue light. Patent Literature 5 (Japanese Unexamined Patent Application Publication No. 2007-150331) discloses a wavelength converter that emits light having a different wavelength from that of incident light by means of a phosphor contained in a composite substrate. Patent Literature 6 (Japanese Unexamined Patent Application Publication (Translation of PCT Application) No. 2005-537679) and Patent Literature 7 (Japanese Unexamined Patent Application Publication No. 2008-010766) disclose art concerning composite substrates. Non-patent Literature 1 (Dmitry S. Sizov, Rajaram Bhat, Jerome Napierala, Chad Gallinat, Kechang Song, and Chung-en Zah, “500-nm Optical Gain Anisotropy of Semipolar (11-22) InGaN Quantum Wells”, Applied Physics Express 2 (2009) 071001) discloses polarization of light emitted from an InGaN well layer.